Effects Of Biochar Amendment To Soils On Life History Of Mythimna Seperata(Walker)on Corn And Wheat

The study of the effect of applying biochar on herbivorous insects can provide data for the the evaluation of the role biochar plays in agriculture.Previous studies have reported that the application of biochar has adverse effects on the development and fecundity of rice planthopper lugens and grain aphid Sitobion avenae.Yet,little has been known about the effect of biochar on insects of chewing and biting plants.In view of marked differences between sap-sucking and chewing insects not only in feeding style but in food utilization physiology and biochemistry,it is of importance to know the biochar effect on chewing herbivore insects.The current thesis research,with the oriental armyworm Mythimna seperata(Walker)as a model system,aims to answer following questions:(1)Whether does biochar application affect the development and fecundity of M.seperata?(2)Whether does host plant influence the effect of biochar on M.seperata.The results from the laboratory experiment indicated that biochar application impaired M.seperata developmental performances,and such effect was stronger on corn than on wheat;biochar application did not influence female fecundity.These results provide new data for the evaluation of biochar applications.1.Effects of biochar on the development of M.seperata on corn and wheatUnder the control,females required 26.0 d to develop from eggs to adulthood when feeding corn leaves;this time was significantly shorter than that(26.7 d)of females feeding wheat leaves at the 1.5%biochar treatment.Pupation rate on corn decreased to 78.21%under the 3.0%biochar treatment.The addition of biochar significantly affected the egg-to-adult time of females on corn.Female egg-to-adult time was 26 d in the control group,decreased to 25 d at the 1.5%rate,while increased to 27 d at the 3.0%.The addition of biochar had a significant effect on female pupal body weight,which was average 0.2265 g in the control,0.2008 g at the 1.5%addition,and 0.2539 g at the 3.0%.Biochar amendment affected male pupal body weight,which was 0.2539 g at the 3.0%amendment and heavier than that(0.2343 g)at the 1.5%level.The addition of biochar had no significant effect on the egg-to-adult time of M.seperata on wheat.It had a significant effect on male pupal body weight,which was 0.2674 g in the control,decreased to 0.2350 g at the 1.5%biochar treatment.2.Effects of biochar on the fecundity of M.seperata on corn and wheatBiochar application had no significant effect on longevity and the number of laid eggs of females feeding on either corn or wheat.Female adults lived for 37.73 to 39.76 d and laid 691 to 805 eggs when feeding corn leaves;lived for 37.86 to 38.63 d and laid 756 to 837 eggs when feeding wheat leaves.